PEDBASE.org - The Pediatric Database - Detailed information of IRON DEFICIENCY ANEMIA

IRON DEFICIENCY ANEMIA

DEFINITION:

A disorder characterized by iron deficiency resulting in a microcytic, hypochromic anemia.

EPIDEMIOLOGY:

incidence: most common hematologic disease of infancy & childhood
age of onset:
- 9-24 months of age (inadequate dietary iron)
risk factors:
- see below

PATHOGENESIS:

1. Etiology of Iron Deficiency Anemia

1. Deficient Intake of Iron

cow's milk

2. Impaired Absorption of Iron

Inflammatory Bowel Disease
Malabsorption Syndrome
postgastrectomy
severe prolonged diarrhea

3. Increased Iron Demand

1. Growth States

low birth weight, prematurity, twins
adolescence
pregnancy

2. Cyanotic Congenital Heart Disease

4. Increased Blood Loss

1. Perinatal

2. Postnatal

1. GI Losses

hemangioma, Meckel diverticulum, peptic ulcer, polyp, whole cow's milk

2. Sequence of Changes in Iron Deficiency

depletion of storage iron
- both ferritin and hemosiderin act as iron storage compon-ents with serum ferritin providing a relatively accurate estimate of body iron stores
- decreased hemosiderin content in the liver & bone marrow
- decreased serum ferritin to 1-35 ug/L
decreased serum iron and elevated transferrin (TIBC)
- at this point the pool of storage iron is unable to main-tain the serum iron
- the lack of iron stimulates the transcription of the transferrin protein
- total iron binding capacity (TIBC) is an indirect measure-ment of transferrin
elevated levels of free erythrocyte protoporphyrins (FEP)
- FEP's are heme precursors which accumulate in iron de-ficiency
RBC structure affected
- microcytic, hypochromic, poikilocytosis
decreased activity of intracellular enzymes containing iron
- catalase, cytochromes (c, P-450), peroxidase

3. Dietary-based Iron Deficiency

daily elemental iron is needed for the first 15 years of life to increase the total body iron from 0.5 grams (newborn) to 5.0 grams (adult); to do so 0.8-1.5 mg of elemental iron is needed daily (since only 10% of elemental iron is absorbed from the diet through the jejunum, the daily elemental iron re-quirement is 8-15 mg daily)
1. Cow's Milk Iron Deficiency Anemia
- as hemoglobin levels fall during the first 2-3 months of life, a considerable amount of iron is reclaimed and stored; thus dietary based iron deficiency anemia is very unusual before 4 months of age but becomes common from
- 9-24 months of age
- as the iron content of cow's milk is 0.75 mg/L, at least 10 litres of cow's milk would have to be consummed daily to met the recommended daily iron requirement - thus, infants whose diet consists primarily of cow's milk are at risk for developing iron deficiency anemia - instead of only absorbing 10% of iron, breast-fed babies absorb 49% of the iron from the breast milk

CLINICAL FEATURES:

1. Anemia

1. Hb >70 g/L

pallor

2. Hb <70 g/L

anorexia - splenomegaly (in 10-15% of patients)
irritability - systolic murmer
pica - tachycardia

INVESTIGATIONS:

1. Serum

1. CBC

hypochromic, microcytic anemia
reticulocytes normal or slightly elevated

2. Smear

anisocytosis and poikilocytosis

3. Iron Studies

decreased serum ferritin
decreased serum iron
elevated transferrin (TIBC)

2. Bone Marrow

hypercellular with erythroid hyperplasia
micronormoblastic maturation
decreased hemosiderin on iron staining
normal myeloid lineage

MANAGEMENT:

I. APPROACH

1. Diagnosis

2. Education

3. Goals of Therapy

4. Management Strategies

1. Supportive

2. Diet

3. Iron Supplementation

4. RBC Transfusion

1. Diagnosis

1. Laboratory

microcytic, hypochromic anemia
low serum ferritin and iron
elevated transferrin

2. Therapy

therapeutic response to iron supplementation

2. Education

definition, epidemiology, pathogenesis, role of diet, treatment options

3. Goals of Therapy

to return the hemoglobin to physiological levels

4. Management Strategies

1. Supportive

correct any causes of chronic blood loss
correct underlying disorders, i.e., Malabsorption

2. Diet

decrease intake of cow's milk
use iron-fortified formulas and cereals

3. Iron Supplementation

6 mg/kg/day of elemental iron po tid
treat for 4-6 weeks after the hemoglobin has normalized
should see a subjective improvement in the patient (decreased irritability and increased appetite) within 24 hours of initiating therapy with reticulocytosis peaking at 5-7 days and a return to normal Hb levels between 4-30 days; it may take 1-3 months to replete the body's iron stores
iron supplements
- ferrous sulfate - 20% elemental iron
- ferrous gluconate - 10-12% "

4. PRBC Transfusion

indicated for severe symptomatic anemia
2-3 cc/kg of PRBC's +/- lasix

Pediatric Database - IRON DEFICIENCY ANEMIA

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